Only a new airplane. Most planes are designed for a lot of air and couldn't fly with as many people as can physically fit inside. Cargo airplanes carefully wat

Only a new airplane. Most planes are designed for a lot of air and couldn't fly with as many people as can physically fit inside. Cargo airplanes carefully watch this factor. As a passenger I've been on airplanes that took off with empty seats even though there were people on standby wanting to get on because with the weather they couldn't fly a full plane.